The synthetically modified green fluorescent protein chromophore analogue 3,4,5‐trimethoxybenzylidene imidazolinone (1) yielded five polymorphs (I, II, III, IV, V) concomitantly irrespective of the solvent used for crystallization. The pentamorphic modification of 1 is solely due to the interplay of iso‐energetic weak intermolecular interactions in molecular associations as well as the conformational flexibility offered by a C—C single bond, which connects the electron‐deficient moiety imidazolinone with the electron‐rich trimethoxybenzylidene group. A common structural feature observed in all the polymorphs is the formation of a `zero‐dimensional' centrosymmetric dimeric unit through a short and linear C—H…O hydrogen bond engaging phenyl C—H and imidazolinone carbonyl oxygen. However, the networking of these dimeric units showed a subtle difference in all the polymorphs. The 2D isostructurality was observed between polymorphs I, II and III, while the other two polymorphs IV and V revealed only `zero‐dimensional' isostructurality. The different fluorescence emissions of Form I (blue) and Forms II to V (yellow) were attributed to the differences in π‐stacking interactions. It shows that one can modulate the photophysical properties of these smart materials by slightly altering their crystal structure. Such an approach will aid in developing new multi‐colour organic fluorescent materials of varying crystal structures for live‐cell imaging and fluorescent sensing applications.

中文翻译：

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绿色荧光蛋白发色团（GFPc）类似物的五个伴随多晶型物：通过π堆积相互作用了解光致发光的变化

合成修饰的绿色荧光蛋白生色团类似物3,4,5-三甲氧基亚苄基亚咪唑啉酮（1）产生五个多晶型物（I，II，III，IV，V），而与用于结晶的溶剂无关。1的五态修改完全是由于分子结合中的等能量弱分子间相互作用的相互作用以及CC单键提供的构象柔韧性，CC单键将缺电子的部分咪唑啉酮与富电子的三甲氧基亚苄基相连。在所有多晶型物中观察到的共同结构特征是通过与苯基CH和咪唑啉酮羰基氧键合的短且线性的CH ... O氢键形成“零维”中心对称二聚体单元。然而，这些二聚体单元的网络在所有多晶型物上显示出细微的差异。在多晶型物I，II和III之间观察到2D同构性，而其他两个多晶型物IV和V仅显示出“零维”同构性。形式I（蓝色）和形式II至V（黄色）的不同荧光发射是由于π堆积相互作用的不同所致。它表明可以通过稍微改变它们的晶体结构来调节这些智能材料的光物理性质。这种方法将有助于开发具有不同晶体结构的新型多色有机荧光材料，用于活细胞成像和荧光传感应用。